Grinding and polishing machine



May 30, 1944. L. HERCIK GRINDING AND POLISHING MACHINE Filed June 20.1941 4 Sheets-Sheet 1 May'30, 1944; 1.. L. HERCIK 2,349,964-

GRINDING AND POLISHING MACHINE Filed June 20,1941 4 sheets-sheet 2- I asa v '57 96 95 a2 60 L40 L. [RC/A" I 57% 96!) irramvn' May 30, 1944.

.| 1.. HERCIK GRINDING AND POLISHING MACHINE 4 Sheets-Sheet 3 Filed Jung20. 1941 v a W m a m mm 2 ME. M a 0 Wu H v M N 9/ MM W, w

r w 2 I Patented May 30, 1944 UNITED STATES PATENT OFFICE GRINDING ANDPOLISHING MACHINE Lad L. Hercik, Lakewood, Ohio, assignor to The HillAcme Company, Cleveland, Ohio, a corporation of Ohio.

ApplicationJune 20, 1941, Serial No. 398,886

23 Claims.

This invention relates to abrading. apparatus of that type. in which theabrading element comprises a, flexible rapidly travelling, abrasive beltcoated on one, face with suitable abrading material. In machines of thistype the. belt is usually mounted on a plurality of rolls or pulleys oneof the rolls being the driving roll causing the belt to travel andanother of .therolls being the contag; or pressure roll serving-toengage thev rapidly travelling belt with the work;to be treated in themachine. this type isusually moved past the contact roll: on a suitablework support substantially juxta posed to the contact roll, suitablemeans being provided for applying'pressure between the abrasive belt andthe work;

While the herein disclosed invention. is adapted for use in many typesof grinding, surfacing and polishing machines and while it may also beadapted for producing or treatingsurfaces on many types of material,this invention is particu-.

larly well adapted for use in machines intended for removing scalefromor for abrading or grinding or polishing or otherwise treating; surfaceson relatively thin flexible sheets or stripsof material.

This work, in machines of- This invention is accordingly illustrated anddescribed in an embodiment ina machine.

the plurality of necessarily high speed pulleys,

shafts, and other rapidly rotating elements supported on the housing ofthe machine, partly to the irregularities rapidly developed in the sur--face of the abrading belt by the severe treatment to which the belt isexposed in the machinery at present developed, and partly by theflapping of the relatively long unsupported portions of the rapidlymoving non-homogeneous abrasive belt.

It is well known that the best grinding results in machines of-this typeare obtained by the useof a contact or pressure roll of relatively smalldiameter for holding the belt in engagement with the travelling sheetto.be finished. Due to the fact that, in previously known machines, the

two strands of the abrading belt have generally been eitherapproximately parallel or. have been inclined to each other at an acuteangle, this.

small contact roll has produced asevere bend in the, belt at the contactroll, tending to elongate the. outer periphery of the belt and tocracklthe abrading surface and. to break the bond between the abradingmaterial and the'belt, thus causing the abrasive material to loosen orflake off or form objectionable projecting ridges. -As a resultof thenecessarily high peripheralspeed of the belt, approaching velocities of4000 feet per j minute, there is a tendency of the belt to spring awayfrom the contact roll andhence, in pre:

viously known machines of this type, considerable tension has beenapplied to this belt to insure a snug and accurate engagement of thebelt with the face of the contact roll thus subjecting the belt tosevere strains. As is also known, the driving roll usually is not madema- 1 terially larger than the contact roll and a heavy strain ortension must be applied to the belt to prevent the slipping of the belton the drive roll and to prevent the belt wearing, belt heating, beltjerking, and accompanying belt deterioration and machine vibration whichresults from such slipping. In order to provide ample resilience in thebelt, a relatively long belt has heretofore been provided which wasmounted upon terminal pulleys spaced roportionately far apart. Thisarrangement has resulted in relatively long lengths of unsupported beltwhich have tended to flap or whip thus introducing additional vibrationinto the machine. All of the above circumstances contribute to theintroduction of irregularities in the appearance of the finish formed onthe surface of 'the sheets.

One of the general objects of this invention, therefor, is to provideapparatus of this class which will produce an even, uniform and smoothfinish upon strips or sheets and, the like, which finish will be freefrom irregularities, blemishes or defects resulting from the imperfectfunctioning of the apparatus or abrading belt.

Another object of this invention is to. produce a machine of this typein which the number of rapidly rotating parts are reduced to an absoluteminimum and which Will accordingly be free from the cumulative chatterproducing vibrations resulting from a plurality of rapidly rotatingparts.

A further object is to. produce an arrangement of abrasive belt pulleysin a machine of this class which will eliminate the imposition of severeand destructive bending strains on the belt a grinding machine of thistype in which the j abrading 'belt is supported exclusively by onedriving pulley and one driven pulley or roll and in which theunsupported lineal length of the strands of belt between the pulleyperipheriesis reduced to such a minimum that substantially noperceptible flapping or whipping occurs. 7

A further object is to produce a machine of which actuates mechanism forguiding the abrasive belt.

Fig. 4 is a top plan view of a control device illustrated in Fig. 3.

Fig. 5 is a front elevation of the device shown in Fig. 3, taken fromthe plane indicated by line 5, 5 in said figure looking in the directionof the arrows. r v

Fig. 6 is a front elevation of this improved machine shown, this viewbeing partly in axial section, taken on the planes indicated by line 6,6 V in Figures 1 and 8 and by line 6, 6 in Fig. 14.

Figfll is an enlarged view of a portion of Fig. 6 illustrating themounting of the head shaft in the housing of the machine.

Fig.8 is a transverse section thru the machine taken on the planeindicated by the line 8, 8 in Fig. '6 looking i'n'the directionindicated by the this type in which a relatively large proportion of thelength of the abrasive .belt is continuously being cooled by, engagementwith the periphery of one of the pulleys onjwhich thebeltis mounted.

A. further objectis to produce apparatus of this type .in whichthe-pulleys are so constructed and mounted that a minimum of beltguiding and/or centering correction is required after. the belt has oncebeen properly centered.

A further object of this invention is the pro,- vision of a simplifiedmechanism for controlling the g liding and/or centering ofan abradingbelt travelling over a pair ofspaced pulley without the use ofanauxiliary guiding or control roll or pulley.-

A-further and more specific object of this invention is the provision ofan improved mounting for the head or driving pulley for an abrasive beltin which this pulley is tiltably' mounted for the purpose of guiding orcontrolling the path of the belt, the mounting being adapted to bereadley on, the shaft and to facilitate the mounting of the pulley onthe shaft or the demounting of the pulley from the shaft.

Afurther understanding of the construction and operation and of-themanner in which the novel features of this invention effect the aboveand further objects, will become apparent from the following detaildescription and the annexed drawingswhich set forth certain meansembodying this invention, such disclosed means constituting,.however,but one of the forms in which the principle of. this invention may beapplied.

Referring to the annexed drawings:

Fig. 1 is a side elevation of a grinding and polishing machine embodyingthis invention, this disclosed machine being shown in an adaptation forgrinding and/or polishing continuous metallic sheet strips, this view ofthe machine being taken from the operators'side of the machine and beingpartly broken'away to show certain interior constructions.

Fig. 2 is a diagrammatic view illustrating, detached from the machine,certain elements of the mechanism for controlling the path of travel ofthe abrasive belt and including a wiring diagram and piping diagramdisclosing the cooperative relation between the elements.

Fig. '3 is an enlarged view of a portion of Fig. 1 illustrating acertain air jet control device arrows and showing the power drive forthe machine.

Fig. 9 is a fragmentaryenlarged elevation of certain mechanism'forangularly tilting the head shaft of the machine, this view beingtaken from the plane indicated by line 9, 9 in Fig. 6 looking in thedirection of the arrows and showing the parts-as they appear as viewedfrom the far side of the machine.

Fig. 10 is a' fragmentry top plan View of the parts illustrated in Fig.9.

Fig. 11 is a transverse sectional view thru a portion of the mechanismillustrated in Fig. 9, this view being taken on the I l l l in saidfigure.

Fig. l2'is a similar transverse sectional view of the mechanismillustrated in Fi 9, this view being taken on the plane indicated byline I2, 12 in said figure. i

Fig. 13 isa fragmentary vertical longitudinal sectional view of themechanism illustrated in Figures 9 and 10, this view being taken on theplane indicated by line I3, 13 in Fig. 10.

Fig. 14 is a plan sectional view taken thru the aixs' of the head shafton the plane indicated by line [4, M in Figures 6 and 8.

Fig. 15 is a fragmentary sectional view thru the hub and'head shaft ofthe head pulley, this view being an enlarged View of a portion of Figures 6 and 14.

General features of machine The main portions of this improved grindingand polishing machine may be indicated briefly in general terms asfollows:

The base supporting the operating mechanism of the machine is indicatedat I. On this base is mounted the work supporting mechanism whichincludes a vertically and horizontally adjustable billy roll 4. Alsomounted on the base i is a column 22 upon which is mounted a head frameor housing 25, this housing being vertically adjustable on the column bymeans of a head frame adjusting mechanism including a screw 36 andassociated power driven mechanism. Rotatably mounted in suitablebearings 42 and 46 in the head frame is a head shaft 50 upon one end ofwhich is mounted a power pulley and upon plane indicated by line ing 42serves as a fixed pivot about which tne head shaft may be tilted and theother bearing 46 is shi'ftably mounted so as to providea means fortilting the head shaft and the head pulley, this provision being madefor the purpose of correctively guiding the abrasive belt 9|] in thedesired path of travel. Suitable mechanism for shifting the bearing 46and thus tilting the head shaft is provided in the fluid cylinder H Iactuated by a valve I32 and a suitable device for controlling the valveis provided by the air jet control unit indicated in its entirety atI44, which unit controls the valve and cylinder responsive to lateraldeviations in the path of the abrasive belt. Brake mechanism including abrake drum I62 and brake shoes I65 is provided for rapidly stopping therotation of the head pulley and abrasive belt.

The construction of the above enumerated features will now be describedin detail. For purpose of reference in the following description, theoperators side of this machine, that is the side on which the headpulley is mounted, is designated as the near side, and the side on whichthe power pulley i mounted is designated as the far side of the machine.Also for convenience of reference, the right end of the machine asviewed in Figures. 1, 8 and 14 is designated as the "front of themachine, and the left side of. the machine as viewed in these figures isdesignated as the rear of the machine.

Work supporting mechanism Referring first to Figures 1, 6, s and 1415fthe drawings, the base of the machine is indicated 9 at I this basebeing of suitable proportions to support the working parts of themachine and being constructed of any suitable material and in anydesired manner as by welding or casting. Upon this base are mounted ,apair of stands 2, 2 upon which are mounted. bearings 3,. 3 thesebearings in turn rotatably supporting. a work support in the form of abilly roll 4' of suitable diameter and width to accommodate. the widestsheet for which the machine is designed. The billy roll 4 is adapted tobe adjusted horizontally in the direction of travel of the work, thatis, to the left or to the right as viewed in Fig. 1. This longitudinaladjustment is made possible by slotting the openings in the flanges ofthe bottom I of the stands 2 by means of which these stands are boltedto the base. as will be readily understood from the. indication at .5, 5in Fig- 1. .Eachof the stands 2 may be adjusted individually in orderthat the axis of the billy r011 may be posi- I tioned in parallelrelation to a certain contact pulley 89 hereinafter to be described.

The billy roll 4 is also mounted for vertical movement toward'and fromthe contact roll 89 and fo this purpose the billy roll bearings 3 areeach provided with a base 6 which is slidably mounted in openings 1formed in the upper portion of the stands 2 as best appears in Figures1, 6 and 14. The bases 6 are each formed with centrally disposed bossesin which are mounted the upper ends of piston rods 8. rods are eachmounted for vertical reciprocation preferably by means of fluid actuatedpistons 9 mounted in cylinders Ill. The pistons 9 are simultaneouslyactuated by means of suitable valve devices of any approved designsimultaneously supplying and releasing fluid under pressure to and frominlets and outlets in the cylinders l0.

As clearly appears from Figures 1 and 6, the

These piston.

to abut the lower end of vertically adjustablebushings l2, mounted inhousings l3 centrally disposed within the stands 2. of the collars Hwith the-lower end of the bushings I2 limits the upward movement of thepiston rods 8 and thus fixes the upper position of the bearings -3 andhence the billy roll 4.

It Will be evident that the upper position of the billy roll must beadjustable to accommodate various thicknesses of the work, variousdiameters of the contact roll 89, etc. For this purpose the bushings l2are made vertically adjustable in order that collars II on the pistonrod 8 may engage the bushings at different vertical positions thereby tostop the bearing 3 and billy roll 4 in the desired upper position.Forpurposes of adjustment, the bushings are provided at their lower endswith threads l4 engaging similar threads formed in the housings l3. Attheir upper ends the bushings are formed with spiral teeth l5 adapted tobe engaged by worms It is also essential that an independent verticaladjustment may be provided for each bearing 3'in order that the axis ofthe billy roll 4 may be disposed accurately parallel with the contactroll 89. In order to permit this independent vertical adjustment acoupling l9 (Fig. 6) is provided in the Worm shaft I 1 which, whendisconnected, will permit the individual adjustment of each of thebushings S2 in order that the proper alignment of the axis of the billyroll may be obtained.

A strip or sheet of material to be finished in this machine is indicatedat .W and rides upon the upper surface of the billy roll 4 as clearlyappears in Figures 1 and 6. This strip W is usually continuous and maybe of any desiredwidth within the capacity of the machine and mayconsist of steel, stainless steel. Monel metal, "bronze, zinc. or othermetallic or non-metallic materials which are to be ground, polished,satin finished, buffed or otherwise treated in this machine. It willappear that the strip W is deflected upwardly slightly about the billyroll and suitable auxiliary rolls may be provided for:

grinding en agement of the strip W with the abrasive belt all mounted onthe contact pulley 89.

The devices for feeding and tensioning the strip are also well knownand. as they form no part of this invention. are not shown. It is to beunderstood however. that the strip feedin devices are presumed to bemanually reversible under.

the control of the operator.

Column andhcad frame support Supported on a pad 2! formed on the'base Iis The engagement a preferably hollow irectangular column 22 as to-seatupon thefaces and sides of'the ways 23.

Guideor clamp bars 21, Fig.g1 l, are provided to hold the housing insliding engagement with the ways: Suitable 'gibs-may be provided toadjust the. tightness oft-he sliding engagement of the housing on thecolumnways, as will be undert od '..V

. The upper end. o-fthe head frame or housing 25 is formed with ahollowgenerally semi-cylindrical portion 26 whose-axis is disposedhorizontally, that is,- transversely of 'the ways 23 of the column..Forming. acontinuation of the portion 28 and extending laterally fromthe housing'25 toward the near or operators side of the machine-is apreferably tapered hollow portion 29. This portion 29 extendsfor aconsiderable distance laterally of the ways 29 and column 22', as bestappears in Figures 6 and 14. The portion 29 is formed at its outer endwith a recess 36:adaptedto receive a bearing 42, to be hereinafterdescribed. Adjacent the far side of the portion 28*thehousing isformedwith seat 3| upon'which is mounteda bracket 32-which in turn supports abearing 46 by means of mechanism to be described.

-:Formed adjacent the lower edge of the head frame 25 is an outwardlyprojecting lip 33 which supports a vertical-plate 34 secured to the faceof the frame 25 and serving as a base plate for the motor 8i.

Head, flame; adjusting mechanism Fixedly mounted on the rear face of thehousing is a nut 35 engaged by a vertical screw 36 (Fig. 8). The lowerend of this screw is sup ported in bearings 31 preferably mounted in thebase of the column 22. Adjacent the lower end of this screw is mounted aworm gear 38 which is in turn driven by means of a suitably mounted worm39. The worm 39 in turn is driven thru a pair of spur gears 40 by meansof a motor 4|. It will appear that the rotation of the screw 36 willadvance the head frame upwardly or downwardly depending upon thedirection of rotation.

Head shaft mounting anti-friction rollers 48 and an inner rac e 49,

Mounted in the inner races and 49 of the bearings 42 and 46 is amain orhead shaft indicated in its entirety at 50.

The outer race 43 of the bearing 42 is clamped between a tongue formedon a cap 5i and a shoulder formed at the inner end of the recess 30, andis thus axially fixed with respect to the housing 25. The inner race 45of the bearing 42 is fixed to the shaft between a shoulder 52 formed onthe shaft and a nut 53 having threada to the housing 25.

The inner race 49 of the bearing 46 is fixed to the shaft 59 between ashoulder 54 formed on the shaft and a nut 55 having threaded engagementwith the shaft, as will appear from an inspection i of the right end ofFig. '7. The outer race 41 of the bearing 46, however; is axiallyslidably mounted in a cylindrical bore 56' formed in a bearing block 51supported for horizontal shifting in the bracket 32 and as will appear,space is provided to permit such relative axial shifting. I

The bearings 42 and 46 are each preferably of the self alining typewhich permit the limited angular tilt of the shaft with respect to theouter race and the bearing housing, this pro- 7 vision being. made for apurpose to be hereinafter pointed out. i

Suitable enclosures and protective seals are preferably associatedwiththe bearings 42 and 46 all as clearly shown on the drawings.

Power pulley on head shaft At the far or right side, as viewed inFigures 6 and 7, the shaft is formed with a'portion 59- extendingoutwardly toward the far side beyond the bearing 46 upon which a headshaft power pulley 66 is mounted, this pulley being fixed againstrotation on the shaft by means of a key 6| and formed with a rim 62 toreceive driving belts, as will bedescribed.

Head pulley and mounting on' head shaft Extending outwardly toward thenear side of Y the machine from thebearing 42 and extendingwhich hub ismounted on the shaft portion in. an.-

improved manner to be later described.

The head pulley 64 comprises a plurality of webs indicated at 66, '61and 68 supporting a rim or shell 69, as best appears. from Figures 6 andThe webs 66 and 61 are positioned in radial planes adjacent the outerand inner ends of the hub and the web 68. is principally conical andflares outwardly from the web 61 adjacent the hub toward the rim 69 towhich it is connected.

It is to be noted .that the rim 69 is formed with a substantiallystraight face and. is considerably wider than the length of the hub andthat the rim is substantially alined with the outer end of the hub atthe near side of the machine and thatthe rim projects well beyond theinner end of the hub and overhangs not only the bearing 42 but also thesection 2.9 of the housing 25 and, as will further appear from the.drawings,

the rim 69 is symmetrically disposed about the center of the bearing 42.

The bearing 42 may accordingly be said to be disposed within theconfines of the pulley 64 and is in fact preferably disposedsubstantially centrally of the face of this pulley.

It will be evident that the head pulley 64 being of relatively largediameter and wide face is necv essarily of considerable weight and'difiicult to handle particularly in assembling upon and re'- movalfromthe shaft end 63 upon which it is 6 .mounted. It is also to be notedthat centering of the head pulley on the shaft 50 and its axialalinement with the shaft must be perfect in order that the head pulleymay run absolutely true and perfectly balanced, not only in the originalinstallations but also in the event of a re-mounting or replacement ofthe pulley on the shaft. It

7 is also evident that an extremely tight fit between the bore of thepulley and the shaft resultingin the adhering of the pulley to theshaftis seriously objectionable not only because of the difficulty ofremoving the pulley but also because of the danger of springing ordistorting the shaft in assembling the pulley on the shaft or demountingthe pulley from the shaft.

In order to facilitate the mounting. and demounting of the relativelyheavy head pulley 64 with respect to the shaft, an improved arrangementof parts is provided, which is best .shown in Fig. 15. Referring to thisfigure, the outwardly projecting portion 63 of the head shaft 50 isformed outwardly beyond the bearing .and preferably adjacent the sealingcap 5.! on the head frame with an outwardly converging conical portion10 extending outwardly for about one third of thelength of the hub 65 ofthe head pulley 64. Beyond the end of the conical portion 70 the shaftis formed with a cylindrical portion ll extending outwardly to a pointnearly flush with the outer end of the hub 65. Outwardly be yond thecylindrical portion 7|, the shaft is formed with a threaded extension.12.

The bore of the hub 65 is formed atits, inner end with an inwardlydiverging conical surface 13 preferably accurately conforming to thesurface on the conical portion 1a of the shaft. Outwhich in practiceneed not necessarily be more 1 than a few thousandths of an inch.

Mounteduponthe threaded extension 12 is a collar or nut ll having athreaded bore engaging the extension 12 and formed with ,an inwardlyconverging conical portion 18 accurately conforming to the outwardlydiverging conical surface 16 in the hubof the pulley. The .collar or nutH is additionally formed with areoess on its inner face, this recessbeing formed with a cylindrical surface 19 whose inner diameter is arelatively tight but rotatable fit on the outer diameter of thecylindrical section II of the shaft, which serves to accurately centerthe nut 1'! on the shaft 50. The nut is provided with a suitable slotfor turning. I I

A key 80 is preferably provided engaging suitable keyways in the shaftand pulley hub to serve as a means for rotatably 'fixing the pulley tothe shaft.

In assembling the pulley64 on the shaft it will be apparent that-theenlarged end of the outwardly diverging conical opening 13 in the hub 65will readily pilot the pulley 64 on :the shaft 50, whereupon the pulleyis moved inwardly 'until the conical surface 13 of the hub is seated on,

the conical portion 1-0 of the shaft. The nut 11 is then screwed on thethreaded extension '12 of the shaft, the nut beingaccurately'axiallycentralizedand alined with the shaft by the engagement of thecylindrical surface '19 with the cytension .ley hub. The outer end ofthe pulley is then free of a crane or .other convenient facility :motor81 this motor any desired manner adapted to adjust the .84 formed with.a plurality .of grooves.

lindrical portion -'H of the shaft until its conical surface 18 engagesthe conical recess 16 in the hub.- A further advancing of the nut willsimultaneously force the inner end of the pulley hub into a firm seatingposition on the conical portion Ill of the shaft and willaccuratelycentra'lize and axially aline the outer end of the pulley withthe shaft, thus insuring the rigid coaxial mounting of the pulley on theshaft.

When the pulley is to be demounted from the shaft, the nut 11 is backedoff the threaded ex- 12 to release the thrust against the pulto tiltdownwardly toward the shaft :to the extent of the limited clearancebetween the cylindrical bore T5 of the pulley hub and the cylindricalportion H of the shaft. If the pulley is so firmly seated on the conicalportion III that it will not readily free itself, a slight tiltingstress applied to [the rim of the pulley aided, if necessary, bya slowrotation of the shaft release of the pulley from the conical portion 13whereupon the pulley may be removed by the use It will be evident thatthe above construction readily permits the assembly and demounting ofthe pulley without any scoring or distorting of the mating parts andthat the pulley may be demounted and reassembled frequently withoutaffecting the accuracy of the mating parts and that a damaged or wornpulley may be replaced by .a new pulley and that an accurate coaxialalmement of the pulley with the shaft is assured at each assembly.

Drive for head pulley Mounted on the vertical plate 34. is .an electricbeing secured to the plate "which have slotted engageas shown at 82 inFigures screws 83 are mounted in in the plate '34 and are position ofthe .motor verto the plate '34 and hous- Mounted, on the motor ishaftvis .a pulley Mounted in the grooves 84 andonthe rim .62 of the "power 34by means of bolts ment with the plate 6 and 8. Adjusting tically withreference ing 25.

pulley '60 are a plurality of V belts 85... It. will appear that by thisarrangement the rotationof the motor will be effectively transmitted tothe head shaft 50 and pulley .64 without vibration. Asxwill beunderstood, the proper tension may be imposed on the V belts .85 bysuitable vertical adjustment of the motor :by means :of theadjustingscrews 83.

Contact pulley and supports accordingly fixedly mounted withreference tothe base I and is substantially parallel to the head pulley .and isbelow and slightly forwardly positionedxwith reference .tozthe axis ofthe head pulley 54. It. is to be noted, howeventhat the contact ipulleyisnot positioned forwardly beyond the periphery of the head pulley, thatis, the contact pulley is located between parallel vertical planespassing thru the axis of xtheheadppulley and tangent to the periphery ofthe. head ,pulley respectively, and as will .also be evident, the

will quicklyeffec-t the upper periphery of the contact pulley issubstantially horizontally alined with the lower periphery of the headpulley, this arrangement just pointed out producing a construction ofthe maximum compactness.

The axis of this contact roll as will appear from Figures 1 and 6, isspaced from and is positioned above and substantially parallel to thebilly roll 4 in the normal position of that roll..

This contact pulley may be made of any suitable solid or laminatedmaterial but I have found that contact pulleys made of rubber, syntheticrubber or similar resilient materials ar most efficient in service.

Y v Abrasive belt and mounting A flexible endless abrasive belt 90 ismounted on the head pulley B4 and contact pulley 89,

this belt consisting ofa paper or fabric base or bacl ing materialcoated on the outer face with flabrading or polishing material suitablefor producing the type of finish desired-on the work W.

, The relation between the head and contactqpulley and their relation tothe abrasive belt are {considered essentially novel features of this in-,vention and their relation may be pointed out as than I one sixth offollows: ,As will best appear from reference to Fig. 1, the diameter ofthe contact pulley 89 is less the diameter of the head pulthat the bestresults are obley 64 and I find tained with a diameter ratio for thesepulleys of substantially one to eight. As will also be clear,

the head pulley and the contact pulley are spaced extremely closetogether, so close togetherin fact that the axes of the head and--.-contact pulley are spaced from each other a. dis- ,tance less thanthe diameter of the head pulley. lyhave further found it desirable tospace the periphery of the contactpulley clos to the ad- ;iacent portionof the periphery of the head pulley and for this reason I prefer tospace the peripheries of the head and contact pulleys apart a distancesubstantially equal to or less than the -length of the periphery of tionresulting from flapping or whipping and it will appear that theunsupported length of each of the strands 'does not exceed '1 times thethe contact pulley.

: Referenceto Fig. 1 will also disclose the fact that the included anglea between the unsupp'orted strands-90a, 90a approximates 90 and is infact substantially greater than 80. 7

"Reference to Fig. 1 will also disclose the as that the abrasive belt 90engages an extremely large portion of the periphery of the head pulley,"the angle of contact being indicated at A andbeting actually in excessof 260. This extensive area of contact between the abrasive belt andtheahead pulley insures an absence of slipping between the driving headpulley and the belt even when the tension on the abrasive belt isrelatively low in intensity.

It-is further to be noted that the abrasive belt becomes severely heatedas a result of the abrad- 'ing action between the belt andthe work, thustending to deteriorate .the belt. This heat is usually intended to becarried away by relatively long lengths of unsupported strands of thebelt which are in contact with air. While, these long, unsupportedstrands have certain disadvantages pointed out, it is also well knownthat air is a poor conductor of heat, and I have found that the long areof contact of the belt with the head pulley makes possible asubstantially complete abstracting of the heat from the belt due to therelatively high heat conductivity of the metal rim of the pulley, thisrim being cooled by the air flowing centrifugally outwardly against theinner face of the rim. As will appear, well over 50%, 70% in theembodiment shown, of the total lineal length of the belt engages theperiphery of the driving pulley.

It will appear that a proper tension may readily be applied to this beltby suitably vertically moving the housing 25 which in turn supports thehead shaft 50 and head pulley 64, whereby the center to center distancebetween the head pulley 64 and relatively stationary contact pulley 89may be varied.

This abrasive belt is preferably driven in the direction indicated inthe drawings by arrows. As is well known, it is extremely diflicult tomaintain a web travelling in a fixed path when the web is travelling onstraight or substantially straight pulleys unless the path of the web iscontrolled by suitable devices. This is particularly true in the case ofabrasive belts in which difierences of strength, thickness, pliabalityand other differences may initially be incorporated in the belt or inwhich such differences may progressively develop as the belt is beingused due to changes in thickness or character of the abrading coating-or backing. For this reason it becomes necessary in machines of thecharacter described in this application to provid means for returningthe belt to the desired path when it deviates from this path. Many andvarying types of devices have been developed for controlling the path ofsuch travelling webs, most of which devices include the provision of anauxiliary roll which is suitably manipulatedto correctively guide theweb, this roll being actuated by some type of a control device which isactuated responsive to deviations in the path of the travelling web.

The herein described embodiment discloses an improved method of guidingthe abrasive belt in the desired path. This method consists of angularlytilting the head or driving pulley about a pivot point within theconfines of the pulley, this pivot point being preferably located on thegeometric center of the pulley. In the present instance this pivot pointis located at the point 0 defined by the intersection of the axis of theshaft 50 and the radial plane passing thru the center of the selfalining bearing'42. In the embodiment disclosed, the shaft 50 and hencethe pulley 64 is tilted by displacing the axis of the shaft 50horizontally in opposite directions from a normal position, themechanism for effecting this horizontal tilt being controlled by anactuating device which responds to deviations of the belt from thenormal path. The mechanism for horizontally tilting the head or drivingpulley wilI now be described.

Head pulley tilting mechanism As previously described, the shaft 50 ismounted in bearings 42 and 46, the bearing 42 being fixed in the housing25 and serving as a pivot about which the shaft may be angularly tiltedand the bearing 46 being supported in a horizon'tally shiftable bearingblock or housing 51. This block 51 is provided at its lower edge with ahorizontal track member or race 9I supported on an anti-friction rollerstructure 92 which is.

in turn supported on a track or race 93 fixedly secured to the bracket32 as best appears in Figures 7 and 9. Serving as an additional overheadguide for the bearing block 51 are a track or race .94 mounted along thetop of the block, an antifriction roller structure 95 and a race 96secured to an upper Ihorizontal wall of the bracket 32.

As will be understood, the bearing 46 and the bearing block 51 andassociated parts are readily shifted horizontally with a minimum ofmechani-:

cal effort.

FiXed tothe bearingblock 51 at the rear end orleft'end of the machine asviewed in Figures 8 and 14, or on the right end as viewed in Fig. 9, isa pin-:9! upon which is mounted a telescoping. frame. "i.h is framecomprises upper and lower outer frame elements 98 and 99 which aremounted on the pin 91. Slidably engaging the elements 98 and 99- areupper and lower inner frame elements I69 and I6I, which are mountedon apin;

I62 parallel to andspaced from the pin 91, upon which pin I92 is alsomounted the head of an eyescrew I93. The shank of the eye screwis formedwith a thread as indicated at I66 and is mounted for axial slidablemovement in a pair of v spaced bosses I64 and 165 formed on the bracket32. Mounted on the shank of the eye screw and formed with a threadedbore engaging the thread I66, is a bevel gear I61. Meshing with thisbevel gear is a bevel pinion I68 suitably mounted on a-shaft rotatablysupported in a boss I69 on the frame 32 and adapted to be rotated by anysuitable manual or power means such asthe hand wheel II'6 shownadjacentto the boss I69 in Fig. .8, but which may be located at anyposition conveniently accessible .to the operator.

Interposed between the pins 91 and I62 is a fluid actuated cylinderconstruction comprising a cylinder I I I, having ears mounted on the pinI62 and a piston actuated rod I12 mounted upon the pin 91. The pistonrod and cylinder are preferably axially alined withtheeye screw I66 andhorizontally alined with the shaft 56..

Integrally formed with and projecting upward- I 1y from the upper outertelescoping frame ele-* ment 96 and adjacent the respective endsof thisframe element are ears H3 and I I4 having alined apertures in which arereciprocably mounted plunger rods I I5 and I I6. The upper inner frameelement I96 is also formed with an upwardly projecting ear I I1 thisearpassing thru a slot or recess in the element 98 and projecting upwardlybeyond the uppersurface of. the element 98 .and

,being formed with an aperture alined with the apertures in the ears; H3and H4 and adapted tosupport theradjacent ends of the plunger rodsII5'and H 6 as best appears in Fig. 13. Collars H6 and H9 are formedintermediate the ends of each of the plunger rodsx-II5 and H6, theseubalancedhorizon'tal component of the tension of V .the abrasiveandipower belts. Nuts I22 and I23 1 having threaded. engagement'with theouter ends 0f the plun er rodsare'provided to suitably posil t-ion thecollarsIlfl and I19 with respect to the ears I I3 and. I'I4,as bestappears in Fig.-l3. The ear H1 is formed-with a lateral offset portionI24, this offset portion being alined with adjustable stop screws I25and I26 mounted in bosses on the element 98 and serving to limit themovement'of thescrews I25 and. I26 and hence the element 98 with respectto the element I69-.. I The lower elements 99 and IllI are each pro-'vided'with ears, plungers, springs, and adjusting screws identical withthose described with reference to the upper elements 98 and I66 as shownin the drawings. 6

The cooperation between the .parts just described is as 'followszfiThebosses I64 and I65being integrallyfnrmed with .the bracket 32 -arerelatively to the housing 25. Theeye'screw 63 altho slidably mounted inthe bosses I641and l- 6 5 can'be longitudinally fixed with respect tobosses by the bevel gear 191 at any position within the range of theadjustment. .Thus I the pin'i62 and'the members I66 and :I6I ineludingthe ears H! can be longitudinally fixed with respect to the frame 32;.Thesprings I26 and are relatively stiff and are so selected that they:wvill. transmit anylongitudinal movement or adjustment of the ear IIItothe. ear H3 orto th f ear H14 :and thence to the elements: 63 and 99and "thus to the .pin 91 and to the bearing block5'l. It is to be notedthat the strength .of the springs I26 .and-IZI is cons'iiderably greaterthan the resistanceto horizontal movement offered by theanti-frictionally mounted bearing block 51; .It will appear from theabove description that a change in the longitudinal position of theeyescrew I63 and pin 6 I62 will produce a corresponding change .in thehorizontal position of :the bearing block 51 and hence of theibearing'46and of the far end of the shaft 56.

Assuming that the bearing block 51 has been located in the desirednormal or neutralposition the manner described; if air is admitted tothe cylinder III thru asuitable inlet I2I the piston 142a and piston rodH2 and pin 9I .wi1l bemoved to the left as viewed inl ig. 9 thuspositively moving the pin- 9'I,.elements 98 and :69 and bearingblock 51to the left and compressing thespringsIZI. The extent of this movementis limited, however, by the abutting of the stop screxv I26 against theoffset portion I24 on the ear II'I after which abutment no furthermovement of the piston can take place. This admission of air thruthejinlet I27 accordingly causes a horizontal shift in the bearing 46and the far .side of the shaft 56 to the extent permitted bythe stop.screw I26. As soon as the air pressure is released thru the opening62-1, the spring I2I again expands until a conditiono-f equilibrium .isestablished between the springs I26 and I.2I whereupon theparts willagain have been returned to the positions shown in Figures 9, 10 and l3.y

If, on the other hand, air pressure is admitted to the inlet openingI29, the piston H21; and piston rod II2 are moved toward the right asviewed in Fig. 9, causing the pin 91 likewise to move toward the rightthus moving the bearing blockfi! and the elements 96 and 99 toward theright. This movement causesthe springs I26 to be compressed and causesthe bearing 46 tomoye to theright .(as viewed in Fig. :9) the extent ofthis movement being. limited by: the abutment ofgthe stopv screw, I25against the ear III. Upon the release of theair pressure thru theopening I28 .theparts will again resume the neutral positions shown inFigures 9 and 10 by the springs I20.-

expanding action of the 1 It will be evident from the above that if thepassage of air to the cylinder is :suitably controlled the piston in thecylinder III and hence the piston rod IiIZ will cause the bearing 46 tobe horizontally shifted in either direction from its normal or neutralposition. It will also be evident, particularly from an inspection ofFig.

14, that the shiftingof the bearing 46 will-cause the head shaft 50 andhence'the head pulley 64,

'to tilt about the'center c of the fixed or pivot bearing 42. Thistilting will be clockwise or counterclockwise as viewed in Fig. 14depending upon the direction of the actuation of the piston and nismbeing illustrated inFig; 2. In this figure,

an air pressure supplytank is diagrammatically shown at I30 from which asuitableair inlet I3I-leads to the four way solenoid actuated valve I32.From this-valve a line I33 leads to the inlet opening I21 at the headend of the cylinder 3 III and a corresponding line I34 leads to theinlet opening I28 at the piston rod-end of the cylinder. Suitable airexhaust openings I35, I35

are provided in the air valve I32 to permit the air pressure applied tothe piston to escape when the piston is to .be returned to the neutralposi- 'tion or is tobe reversed. This air valve may be of any well knownstandard design and since this valve per se forms no part of thisinvention it? need not be described in detail.

, -Device s for controlling tilting mechanism The control device foractuating the head pulley tilting mechanism will be best understood byreference to Figures '1 to 5, inclusive, and comprises electricallyenergized solenoids shown at "I36 and I31 these solenoids being mountedin any convenient position on the frame of the ma- "chine, in suitablerelation tothe valve I32. Each solenoid I36 and I31 is provided with avertically movable plunger indicated at I38 and I39, re,- spectively.Also supported on the frame of the machine in suitable relation to thevalve I32 and solenoids I36 and I31 is a pair of bell crank levers I40and MI each associated with one of the solenoids and adapted to actuatethe :four way valve I32 to'introduce air under pressure .int'o'one orthe other of th lines I33 or I34 running to the cylinder III. As'shownin the drawings, the solenoid I31 when energized is adapted to actuatethe valve I32 to introduce -'=air under pressure thru the line I34 andinlet -I28 into the piston rodlend of the cylinder III and the solenoidI36 when energized is adapted to introduce'air under pressure thru theline I33 and inlet I21 into the head end of the cylnder. v

The solenoids I36 and I31 are selectively and intermittently energizedby a control device indicated in its entirety at I44 and includingelecfrom a predeterminednorrnal path.

: The solenoid I35'is associated with the circuit I45 which is adaptedto be energized by the .switch. I41 and the solenoid I31 is associatedwith the circuit I46 which is adapted to .be energized bythe switch I48,as appears in Figures 2.,to 5 inclusive. The above described solenoidcontrolled valve mechanism and the control device I44 are in principalsubstantially similar to the corresponding elements disclosed in mycopending application Serial No. 337,326 and the herein disclosedcontrol device is practically identical with the device, illustrated inFigures 11 to 15 of that application, and need only be briefly describedhere. The. present control device, like the earlier device just referredto is located adjacent one edge of thetravelling belt and is responsiveto the movement of one edgeonlyof the travelling belt and'is preferablypositioned generally symmetrically about this edge of this belt ,asrwillappear bestfrorn reference to Figures 2, f1 and 5 of th presentapplication.

.The mercury switches I41, and I48 are supported in a suitable casingI49 this casing being mounted on an air inlettube I50 which is axiallyand rotatably adjustably mounted in a bracket I5I preferably supportedfrom one of the contact pulley stands 86 as shown in Figures 1, 6 and14. It will therefor be seen thatthis casing may be laterally shiftedwith respect to the belt to locate the control devices in variouslateral positions corresponding to the desired or necessary location ofthe edge of the belt which is intended to actuate the devices. A setscrew or other suitable means may be used for fixing the casing and.tube I50 in the desired position.

The mercury switches I41 and I48 are each formed with two spacedcontacts located at one end of an enclosing glass tube, these contactsmaintaining the circuit open when the tube is tilted to position themercury in that end of the tube opposite the contacts. These mercuryswitches are each mounted on a shaft pivotally supported in the casingpreferably in anti-friction bearings. Also mounted on these shafts andat points on opposite sides outside of the casing are controllevers I52and I53, the lever I52 being associated with the mercury switch I41 andthe lever I53 being associated with the mercury switch I48. The controllevers in the embodiment shown, pass upwardly around the respectivesides of the casing I49 and toward each other and toward the center ofthe casing as is best shown in Fig. 5. At the inner or adjacent ends,these control levers are each provided with a relatively light flatplate, vane or spoon, indicated. at I54 and I55 respectively,

adapted to serve as an abutment for spaced jets of air presently to bereferred to. The leversI52 and I53 and vanes I54, I55 normally assume aposition by gravity, each resting against a stop pin, this being theposition occupied by the lever I52 and vane I54, as bestappears in Fig.3. Secured to the upper face of the casing I49 is an angle brackethaving a vertically disposed wall portion substantially paralleltothewall I56 in which portion a pair of nozzles I and I6I are located, thesenozzles being axially alined with the apertures I51 and I58,respectively. Air under pressure is supplied to the inlet tube I50 andthence to the branch tubeil59 this air issuing fromthenozzlesinrelatively fine. streams which, unless obstructed; pass *thru the.aperturesi'l5'l and I58 and impinge against the vanes I54 and I55 andwhich have sufficient kinetic energy to overcome. the slight" force ofgravity acting on the vanes and" associated parts thus tilting theassociated vanes, levers and mercury switches from the position whichthey normally occupy by gravity.

As will appear, the nozzles are positioned adjacent the rear or smoothface of the belt, that is on the opposite side of the'abrasive belt fromthe wall I56 and vanes I54 and I55, and are positioned to straddle theedgeof thebelt when the belt is travelling in the desired path, asclearly shown i'nFigures 2 and 4. As a; result of the arrangementdescribed, the air jet from the nozzle ISO, in normal operation,impinges against the belt'being thereby blocked fromimpinging againstthe vane I54 and thus permitting the vane I54 and associated lever I52and switch I41 to assume the position which itnor mally occupies bygravity, while the air'jet from the nozzle I6I passes past the edge ofthe belt thru the aperture I58 and impinges against the vane I55 thusdisplacing the vaneul55 and associated lever I53 and switch I48 from theposi tion which it would normally-occupy by gravity; The terminals inthe mercury switch I4'I are so positioned that the circuit controlled bythe switch I4! is open when the switch and vane are in position shown inFig. 3, that. is the position which they occupybygravity; The switchI48, on the other hand, is so arranged that the circuit controlled bythe switch is open when this switch and vane are in the position shownin Fig. 3, that is when the associated air jet I6! is impinging againstthe vane.

It is to be noted that two stop pins are provided on each sideof thecasing I49 to serve to stop the levers I52 and'l53 in the desiredterminal positions as best illustrated in Figures 3 and 4. Both of theswitches I41 and I48 are arranged to close the respective circuitscontrolled by them when the switches are respectively in the alternatepositions from those shown in Figuresl to 5'; that is when thellever I52is forced against the right hand pin and when the lever I53 is restingby gravity against the left hand pin as viewed in Fig. 3. The wall I55is providedprimarily to'protect the delicate vanes and controllevers'from serious damage in the event of a tear or break in theabrasive belt.

Head pulley brake The'momentum. of the head pulley dueto its large sizeand comparatively rapid rotation is relatively great and due to theanti-friction mounting of its shaft normally continues to r0- tate. fora substantial period of time after the power is shut off. In order toeliminate the disadvantages incident to this prolonged rotation, and inorder to provide almeans for rapidly stopping the head pulley in an.emergency, a suitable brake mechanism is provided.

Thismechanism as bestappears in Figures 6 and-8 consists of a brake.drum I62 provided on the power pulley 60 and a bracket I63 mounted, on.the horizontal shiftable bearing block 51 andsupporting a. pin I64 uponwhich are mounted the lower ends of a pair of brake shoes I65, I65.These shoes are adapted to be moved into braking engagement-* with theinner face of the drum by means of a suitable air cylinder I65interposed between the upper or movable ends of the brake shoes. As willbe understood, the suitable application of air pressure to the aircylinder I66 causes the shoes to expand into'engagement with the innerface of the drum and the-rapidity of braking will be proportional to theintensity of pressure applied to the cylinder I66; I

Operation of grinding mechanism The operation of the grinding mechanismof this improved machine will readily appear from the precedingdescription and from the draw ings, supplemented by a brief furtherexplanation.. r

In the drawings, the machine is shown in a non-operating or non-grindingposition but the parts of the machine are assumed to be in correctlyadjusted positions'ready for proper operation and the parts are furtherassumed to be in motion just preliminary to the actual grind: ing. It isaccordingly assumed that the strip W to be ground has. been properlycenteredv on the billy roll 4 and. thatjt has been properly tensionedand that it hasbeen caused to travel. in: the direction indicated inFig. 1. It is further assumed that the abrasive belt hasbeen properlymounted on the large head pulley 64 and on the contact pulley 89 andthat the abrasive belt has been correctly tensioned by verticaladjustment of the. head pulley and that the drive belts have beencorrectly tensioned by vertical adjustment of the drive motor BI andthat the motor has been started, causing. the abrasive belt to travel inthe. direction indicated in the several views. Itis also assumed thatthe head pulley has been properly angularly tilted with respect to thecontact pulley to cause the abrasive belt to. travel in the desiredpath, this tilting having, been effected by the proper horizontalshifting of the bearing 46 by means of the mechanismand method describedhereinbefore under the heading Head pulley tilting mechanism. It is alsoassumed that the. billy roll 4 has beenproperly positioned horizontallyand in parallel relation with reference to the. contact roll 89 and thatthe bushings I2 have been accurately vertically adjusted to properlyspace thebilly roll from the abrading belt to produce the desiredthickness of the finished strip W, this being effected by means of themechanism and in themanner. hereinbeTore'described under the heading ofWork supporting means.

All of the elements of this machine having been properly adjusted andset in motion, as pointed out. air under pressure is simultaneouslyadmitted to the cylinders H! which cause the pistons 9, piston rods 8,bearings 3 and billy roll 4 to move upwardly to the predeterminedposition in which the collars H on thepiston. rod 8 engage the bushingsI2 thus causing the travelling strip W to be positioned in propergrinding relation to the abrasive belt.

The characterof the finish produced by the abrasive belt can immediatelyandclearly be inspected as soon as it emerges from the grinding areathis being made possible by the substantially vertical approach of theabrasive belt toward the If the depth of the grinding is too great ornot suiiiciently deep, corresponding adjustments can be made by theoperator while the grinding progressing by suitably turning thebandwheel til. Means may also be provided to instantly reverse thedirection of travel of the strip W in the event that the initialgrinding has not completely eradicated surface defects and a localorcomplete re-grinding is necessary.

When the grinding of the strip has been completed or when it is desiredto' interrupt the grinding operation for any'o'ther reasonQit isonlynecessary for the operator to'release' the air pressure from the lowerfaces of the pistons 6 in the cylinders lfl whereupon the billy roll 4and the strip W, drop, aided by air pressure on the upper face of thepiston, if necessary, to the position spaced from the beltas shown inthe drawings. If it becomes necessary or desirable to quickly stop therotation of the head pulley 64 this can be effected by applying airpressure to the air brake cylinder I66 in the head pulley brake ashereinbefore explained. I

Operation of belt guiding mechanism Inthe position of the parts as shownin the drawings, the abrasive belt is assumed to be running in thedesired predetermined path. In this. position .of the beltthe nozzlesI60 and l6I are positioned to straddle the edge of the belt as clearlyshown in Figures2, 4 and 5. Accordingly the air jet fromth'e nozzle I60impinges against the belt,,90..and .is, blocked, from, reaching the vanel54thus permitting thelevjer I 52 to gravitationally hold-the switch I41in the open position. The air jet from the nozzle I6I on the other hand,clears the edge ofthe belt 90 and impinges against the vane I55 thusdisplacing the lever I53 from its gravitational position and maintainingthe switch I48 in the open position. r V

Uder the above circumstance, thatis when both switches I41 and, I48 areopen, both solenoids: I36 and .131 are de-energized andthe four wayvalve I32 is, in the position in which it releases the pressure fromboth ends of the cylinder III and the springcontrolled.plungers H5 and II6 maintain the bearing 46 and hence the head shaft 50 and theheadpulley 64 inthefnormal position thus tendingto maintain the webtravelling in the desired predetermined path, these spring controlledplungers, H5 and H6 likewise causing the piston to assume anintermediate position between the ends of the cylinder III.

As pointed out, however, the travelling belt is subject to lateraldeviations from its desired path and the hereinbefore described headpulley tilting mechanism and. control device constitute belt guidingmechanism intended to return the belt to its normal path of travel inthe event that the web hasmeandered, for any reason, from the normalpath and this is effected as follows:

Suppose it be assumedthat the abrasive belt shifts toward the far sideas viewed in Fig. 1, that is to the right asviewed'in Figures 2 and 6..In this event, the edge of the web will approach the jet issuing fromthe nozzle I6I and will eventually intersect the path of this jet andinterrupt or block this jet from reaching the vane I55 on the lever I53.Under these circumstances the vane I55 and lever I53 swing downwardly tothe left bygravity, that is in a counterclockwise direction as viewed inFigures 2 and 3, being freed from the restraint of the jet. The downwardpositioning of the lever I53 causes the mercury switch I48 to close thecircuit I46 which in turn energizes the solenoid I31. The energizing ofthis solenoid lifts the plunger I39, this in turn tilting the bell cranklever I4I to so actuate the four way valve I32 as to introduce air thruthe line I34 into the piston rod end of the cylinder III. This airpressure causes the piston H211 to move toward the head end of thecylinder thus moving the piston rod I I2, bearing'block 51 and bearing46 to the left as viewed in'Figures 2, 8, and 14, that is, to the rightas viewed in Fig. 9, and compressing-the springs 5 I20. This movementcauses'the far end of the shaft 50 "to shift or tilt to the left asviewed in Fig. 14, this tilting or pivoting taking place about thecenter 0 of the bearing 42. This tilting of the v head shaft causes acorresponding tilting of the 10 axis of'th'e head pulley with respect tothe axis of the contact pulley and this counterclockwise shifting of thepulley'about the center 0 as viewed in Fig. 14 tends'to return the beltto its normal position, that is it tends to move the belt pro- 15gressively toward the near side.

After this belt has travelledlaterally toward the near side a'sufiicientdistance to reach substantially its normal path, the jet issuing fromthe nozzle I6I willa'gain'be unblocked, that is it will '20 again clearthe edge of the beltand be free to impinge against the vane I55 on thelever I53, thus'causingthe switch I46 to move to the open position'andthus tie-energizing themagnet I31 whereupon the plunger I39 drops topermit the valve I32 to shift to its neutral position in which the airis released'from bothsides of the cylinder I I l. The pressure againstthe piston having been released, the expansion of the springs I20 againshifts the bearing block 51 to the right as viewed in Fig. 14 andhencetilt the shaft 50 back to its normal running position and the headpulley will again be so positioned that the belt will continue to travelin the normal path. It is to be noted that v the stop screw I25 limitsthe extent to which the 35 shaft 50 is tilted during the correctiveaction.

'If the belt should travel to the near side of the machine, that is tothe left as viewed in Figures 2 and 6, it will unblock the jet issuingfrom the nozzle I60,thus permitting this jet to impinge against the vaneI54 and tilt the lever I52 and switch I41 to a position in which theswitch I41 closes the circuit I45 thus energizing the solenoid I36causing the plunger I38 and associated bell crankI40 to actuate thevalve I32 to introduce air under pressure thru the line I33 into thehead end of the cylinder III which causes the bearing block 51 and thebearing 46 to move to the right as viewed in Figures 2, 8, and 14 thuscompressing the spring I2 I and shifting the far end of the shaft 50 50toward the right and tilting the head pulley 64 in a clockwisedirection, as viewed in Fig. 14, about the center 0. This tilting causesthe belt to progressively traveltoward the far side. This tiltedposition is maintained until the belt has substantially reached itsnormal path at which time the jet issuing from the nozzle I is againblocked by the'belt thus permitting the vane I54, lever I52 and switchI41 to tilt to the position in which the switch is open, thustie-energizing the solenoid I36 and thus controlling the valve I32 topermit the air to escape from the cylinder I I I whereupon thecompressed spring I2 I, again shifts the bearing 46 to the normalposition and tilts the head shaft 50 to its normal running position inwhich it normally maintains the belt travelling in the desired path.

It will be seen from the above description that thetilting of the heador abrasive belt driving pulley and the corrective shifting of theabrasive belt is initiated in response to any excessive deviation fromthe desired predetermined path of travel of the belt.

, General It will be evident that in the herein disclosed belt typegrinding and polishing machine the number of rapidly rotating parts has:been reduced to an absolute minimum and that the proportionately verylarge head pulley reducesthe objectionable vibration producing capacityof the rotating parts of this machine, and that the improved associationof relatively verylarge and very small pulleys eliminates thedestructive bending strains on the-belt, and that the selection of therelativelyvery largedriving pulley reduces the tension which must beapplied to prevent the slipping of the belt, and the relatively closemounting of the large and small belt; pulleys produces a very compactunit, andeliminates belt whipping, and the tiltable mounting of thedriving head pulley about a center within the confines of the pulleyproduces a simplified. mechanism for the guiding and/or centering of anabrading belt traveling over a, pair of, spaced pulleys, and that thismachine, otherwise fulfills. the objects set forth, in the beginning ofthis specification.

Many modifications of this invention. andits application. will.naturally occur, to thoseskilled in this art and the present disclosureshould therefore be considered. as, typical only, and. I desire not tobe limited. to theexact constructions shown and described.

Inasmuch, as this invention is unconcerned with the specific characterof the workmaterialior of the work-treating belt, the terms abrasiveandthe like, and work and the like, used herein. and in the appended,claims are intended broadly to include within their comprehension anyand all materials towhich themachine which constitutes this inventioncantbe applied, as will be understood, by those skilled in the art.

It is to benoted that certain features disclosed in this application andnot claimed herein, are claimed in my co-pending application Serial No.337326 filed May 25, 1940, now Patent No. 2,274,- 268 of February 24,1942: and. in. my co-pending application Serial No. 338,175 filed May31, 1940, now Patent No. 2,316,582 of April 13, 1943.

What I claim is: 1

I. A machine of the character described including in combination, adriving: pulley having a relatively large diameter, a contact pulleyhaving a relatively small diameter. an endless abrasive belt mounted. onsaid pulleys, thebelt comprising two portions engaging the peripheriesof the pulleys and maintained by the pulleys against vibration and twounsupported; strands intermediate the periphery engaging portions, saidunsupported strands being inherently subjected to vibration, the spacingof said pulleys being such that the length of each strand of unsupportedbelt does not exceed one andone half times the length of the peripheryof the said contact pulley whereby the length of belt subject tovibration is kept relatively small, means for actuating the drivingpulley, and a" work support juxtaposed to said contact pulley.

2. A machine of the character described including in combination, adriving pulley'having a relatively large diameter, a contact pulleyhaving a relatively small diameter, an endless belt mounted on saidpulleys and having bonded thereto an abrasive coating which tends toseparate upon severe bending of the belt, the belt comprising twoportions engaging the. peripheries of the pulleys and two unsupportedstrands intermediate the periphery engaging portions, the includedanglebetweenthe unsupported strands being greater than eighty degreesrwhereby. the

bendingxst'resses imposed? on the belt by thecontact: pulley are. keptwithin safe limits, means for actuating the driving pulley, and a worksupport juxtaposed tosaid contact pulley;

3. A machine of the'character described, ineluding in combination, adriving pulley havinga relatively large diameter, a contact pulley having' a relatively small diameter, an endless abrasive belt mounted onsaid' pulleys, the belt'comprising two portions engaging the peripheriesof the pulleys so as to be cooled thereby and two unsupported strandsintermediate the periphery engaging portions; the arc of contact of the'abra sive belt on the periphery of the driving-"pulley being in excessof two hundred sixty degrees so that the cooling effect of said pulleyon the for actuating;

prising two portions engaging theperipheriesof;

the, pulleys so as to, be cooled thereby and two unsupported strandsintermediate the periphery, engaging portions, the lineal, length of.the portion. of. the. belt engaging the periphery. of the driving,pulley comprising morethanfiijty percent of. the, total lineal length ofthe. belt so that the. major portion, of. the belt is at, all:

timescooledbysaid pulley, means for actuating the driving, pulley. and awork posed. to, said, contact pulley.

5. In. a machine of. the character described, a supporting. frame, a.work support; a. rotatable contact pulley juxtaposed to the worksupport,.a

head pulley. rotatably-mounted in theframe,, an endlessabrasive beltmounted onsaid pulleys,:the diameter of said contact pulley being lessthan one sixth of the diameter of the head pulley, the axes of-saidpulleys being spaced from each, other distance substantially less thanthediameter of thehead' pulley whereby the portion of-thebelt which isunsupported.- by engagement with said pulleys is rendered substantiallysmall, power means for driving. one-ofsaid pulleys, and'means formoving; the worksupport radially'towardand away from the contact pulleyso as to control the. application. of the portion of abrasive beltinstantaneouslyon' the contact pulley towork on the worksu-pport;

6. In awmachine ofthecharacter described; a supporting frame, a worksupport; a rotatable contact pulley'juxtaposed' tothe work support. ahead pulley rota-tably mounted in the frame, and endless abrasive beltmounted onsaid pulleys; the diameter of said contact pulley being lessthan one sixth of the diam'eterof'the headpulley and the peripheries ofthe pulleys" being spaced apart a distance less than substantiallythediameter of the contact pulley whereby the'portions of the belt whichare unsupported by engagement With-the pulleys are renderedsubstantially small the included angle between said unsupported portionsis relatively large, power means for driving one of said pulleys, andmeans for moving the work support radially toward .and away fromthecontact pulley so as to, control theapplication. of. the portion of.abrasive belt instantaneously onthe. contact pulley to workonthe worksupport.

support, juxtamounted on ,saidpulleys, and power means for drivingone ofsaid pulleys, whereby the vertical spacing of the axes of the contactand head pulleys is reduced substantially to a minimum and the strand ofbelt extending to work issuing-from the contact pulley is substantiallyvertical so that the effeotof the belt on the work can be observedsubstantially at the line of contact between. the work and the contactpulley.

Y 8. A' machine of the character described including, incombination, anendless abrasive belt, pulleys for. supporting and driving the belt,said pulleys consisting of afdriving pulley of relatively large diameterand a contact pulley of relatively small diameter and said beltcomprising two portions engaging the peripheries of the pulleys andmaintained by the pulleys against vibration and twounsupported strandsintermediate the periphery engaging portions, said unsupported strandsbeing inherently subject to vibrations, means for tilting theaxis of oneof said pulleys for correctively'guiding the belt around said pulleys,the spacing of said pulleys being such that the length of each strand ofunsupported belt does not exceedone and one half times the length of theperiphery of the contact pulley, whereby the length of belt subject tovibration is kept relatively small, means for actuating the drivingpulley, and a work support juxtaposed to the contact pulley.

'9. A-machine of the character described including, in combination, anendless abrasive belt, ,pulleys for supporting and driving the belt,said pulleys consisting of a driving pulley of relatively large diameterand'a contact pulley of relatively smalldiameter and said belt havingbonded there to an abrasive coating which tends to separate upon severebending, said belt comprising two portionsengaging the peripheries ofthe pulleys andtwo unsupported strands intermediate the peripheryengaging portions, the included angle between the unsupported strandsbeing greater thaneighty degrees whereby the bending stresses imposed onthe belt by the contact pulley are kept within safe limits, means fortilting the axis of one of the pulleys for correctively guiding the beltaround said pulleys, means for actuating the drivin pulley, and a worksupport juxtaposed to said contact pulley. v

.10; A machine of the character described including, in combination, anendless abrasive belt, pulleys for supporting and driving the belt, saidpulleys consisting of a driving pulley having a relatively largediameter and a contact pulley having a relatively small diameter andsaid belt comprising .two portions engaging the peripheries of thepulleys so as to be cooled thereby and two unsupported strandsintermediate the periphery engaging portions, the arc of contact of theabras'ive belt on the periphery of the driving pulley being excess oftwo hundred sixty degrees so that the cooling effect of said pulley onthe belt '7. In" amachine of the character described, a supporting;frame, a horizontal'work support, a

is relatively great, means for tilting the axis of one of the pulleysforcorrectively guiding the belt around said pulleys, means for actuatinthe driving pulley, and a work support juxtaposed to said contactpulley.

11. A machine of the character described including,in combination, anendless abrasive belt, pulleys for supporting and driving the belt, saidpulleys consisting of a driving pulley'of relatively large diameter anda contact pulley of relatively small diameter and said belt comprisingtwo portions engaging the peripheries of the pulleys so as to be cooledthereby an two unsupported strands intermediate the periphery engagingportions, the lineal length of the portion of the belt engaging the,periphery of the driving pulley comprising more than fifty percent ofthe total lineal length of the belt so that the major portion of thebelt is at all times being cooled by said driving pulley, means fortilting the axis of one of the pulleys for correctively guiding the beltaround said pulleys, means for actuating the driving pulley, and a worksupport juxtaposed to said contact pulley,

12. In a machine of the character described, a supporting frame, a worksupport, an endless abrasive belt, pulleys mounted on the frame forsupporting and driving the belt, said pulleys consisting of a contactpulley juxtaposed to the work support and a head pulley, the diameter ofthe contact pulley being. less than one sixth of the diameter of thehead pulley, the axes of said pulleys being spaced from each other adistance substantially less than the diameter of the head pulley wherebythe portion of the belt which is unsupported by engagement with saidpulleys is rendered substantially small, means for tilting the axis ofone of the pulleys for correctively guiding the belt around saidpulleys, power means for driving the head pulley, and means for movingthe work support radially toward and away from the contact pulley so asto control the application of the portion of abrasive beltinstantaneously on the contact pulley to work on the work support.

13. In a machine of the character described, a supporting frame, a worksupport, an endless abrasive belt, pulleys mounted on the frame forsupporting and driving the belt, said pulleys consisting of a contactpulley juxtaposed to the work support and a head pulley, the diameter ofthe contact pulley being less than one sixth of the diameter of the headpulley and the peripheries of the pulleys being spaced apart a distanceless than substantially the diameter of the contact pulley whereby theportions of the belt which are unsupported by engagement with thepulleys are rendered substantially small and the included an gle betweensaid unsupported portions is relatively large, means for tilting theaxis of one of the pulleys for correctively guiding the belt around saidpulleys, power means for driving one of said pulleys, and means formoving the work support radially toward and away from the contact pulleyso as to control the application of the portion of abrasive beltinstantaneously on the contact pulley to work on the work support;

14. In a machine of the character described, a supporting frame, a headshaft, a pulley fast on one end portion of the shaft, a pair of spacedbearings'rotatably supporting the shaft, a support for one of thebearings mounted for lateral movement with respect to the frame, theother bearing being pivotally mounted in the frame, said pivotallymounted bearing being interposed between the movable bearing and thefastening for the pulley on the shaft, means for shifting the movablesupport, power means for rotating said shaft, a second pulley fixablysupported relatively to the frame, an endless abrasive belt mounted onsaid pulleys, and work supporting means juxtaposed to one of saidpulleys.

15. In a machine of the character described, a supporting frame, a headframe slidably mounted on the supporting frame, a shaft mounted in thehead frame, a pair of spaced bearings rotatably supporting the shaft atpoints spaced from the ends of th shaft, a pulley adapted to support anabrasive belt mountedon one end of the shaft, a power receiving pulleymounted on the other end of the shaft, one of said bearings beingdisposed substantially centrally Within the confines of the abrasivebelt supporting pulley and the other bearing being disposed adjacent thepower receiving pulley, and means for adjusting the latter bearing in adirection normal to the direction of sliding of the head frame.

16. In a machine of the character described, a supporting frame, anendless abrasive travelling belt, a pair of spaced pulleys about whichthe belt passes, said pulleys consisting of a contact pulley mounted onan axis fixably supported on the frame and a driving pulley, a shaft onwhich the driving pulley is fast, two bearings mounting the shaft on theframe, one being a pivot bearing disposed within the confines of thedriving pulley, a slidable block mounting the other bearing for shiftingthe same to pivot the shaft about the pivot bearing, means connected tothe slidable block to slide the same and thereby shift the path oftravel of the belt, and Work supporting means juxtaposed to the contactpulley.

17. In a machine of the character described, a supporting frame, anendless abrasive travelling belt subject to lateral deviations from adesired path of travel, a pair of spaced pulleys about which the beltpasses, one of said pulleys being a contact pulley mounted on an axisfixably supported on the frame and the other of said pulleys being adriving pulley, a shaft on which the driving pulley is fast, twobearings mounting the shaft on the frame, one being a pivot bearingdisposed within the confines of the driving pulley, a slidable blockmounting the other bearing for shifting the same to pivot the shaftabout the pivot bearing, control mechanism responsive .to deviations ofthe belt from the desired path of travel connected to the slidable blockfor shifting the same, and work supporting means juxtaposed to thecontact pulley.

18. In a machine of the character described, a supporting frame, anendless abrasive travelling belt, a pair of spaced pulleys about whichthe belt passes, one of said pulleys being a contact pulley mounted onan axis fixably supported on the frame and the other of said pulleysbeing a driving pulley, a shaft on which the driving pulley is fast, twobearings mounting the shaft on the frame, one being a pivot bearingdisposed within the confines of the driving pulley and substantiallycentrally of the face of the driving pulley, a slidabl block mountingthe other bearing for shifting the same to pivot the shaft aboutthepivot bearing, means connected to the slidable block to slide the sameand thereby shift the path of travel of the belt, and work supportingmeans juxtaposed to the contact pulley.

19. In a machine of the character described, a supporting frame, anendless abrasive travelling belt, a pair of spaced pulleys about which.the belt passes, one of said pulleys being a contact pulley mounted onan axis fixably supported on the frame and the other of said pulleysbeing a driving pulley, a shaft on which the driving pulley is fast,said shaft having a portion extending out beyond the frame, a powerpulley on the end of said extending portion of the shaft having adriving belt engaged therewith, two bearings mounting the shaft on theframe, one being a pivot bearing disposed within the confines of thedriving pulley, a slidable block mounting the other bearing on theportion of the fram adjacent to the power pulley for shifting said otherbearing to pivot the shaft about the pivot bearing, means connected tothe slidable block to slide the same and thereby shift the path oftravel of the belt, and work supporting means juxtaposed to the contactpulley.

20. In a machine of the character described, in combination, a pluralityof axially spaced shafts, a pulley mounted on each shaft including adriving pulley fast on its shaft, an endless abrasive belt mounted onsaid pulleys, a support for the drivin pulley shaft adapted to permitthe tilting of the shaft, means for correctively guiding the belt aroundsaid pulleys comprising mechanism for tilting the driving pulley shaft,means for driving the tiltable shaft, and brake means including a brakedrum mounted on the tiltable shaft adapted when actuated to retard therotation of the driving pulley, and manually controllable means foractuating the brake means.

21. In a machine of the character described, in combination, a pluralityof axially spaced shafts, a pulley mounted on each shaft including adriving pulley fast on its shaft, an endless abrasive belt mounted onsaid pulleys, bearings mounting the driving pulley shaft including ashiftable bearing and a pivoted bearing, means for shifting theshiftable bearing so as to tilt the shaft about the pivoted bearing forcorrectively guiding the belt around said pulleys, means for driving thetiltable shaft, brake means including a brake drum mounted on thetiltable shaft adapted when actuated to retard the rotation of thedriving pulley, and manually controllable means for actuating the brakemeans.

22. In a machine of the character described, in combination, an endlessabrasive belt, a relatively large driving pulley and a relatively smallcontact pulley about which pulleys said belt passes, tiltable shaftmeans for supportin said driving pulley, power means for rotating saidshaft means,

and brake means including a brake drum mounted on the tiltable shaftadapted when actuated to retard the rotation of the driving pulley andmanually controllable means for actuating the brake means.

23. In a machine of the character described, in combination, an endlessabrasive belt, a relatively large driving pulley and a relatively smallcontact pulley about which pulleys said belt passes, a shaft fixed tothe driving pulley and supporting the driving pulley, power means forrotating the shaft, means for rotatably supporting the shaft includingat least one shiftable bearing, brake means interposed between the shaftand the shiftable bearing adapted, when actuated, to retard the rotationof the shaft and manually controllable means for actuating the brakemeans.

LAD L. HERCIK.

